Equatorial mount for telescope with balanced weight distribution

ABSTRACT

An equatorial mount for providing a telescope with a balanced weight distribution is described. The equatorial mount comprises a base, a declination base, and a device support. The declination base is rotatable about a right ascension axis relative to the base. The device support is rotatable about a declination axis relative to the declination base. The declination axis intersects orthogonally with the right ascension axis and the declination axis intersects a midsection of the declination base. The declination base comprises a counterweight assembly extending along a counterweight axis, the counterweight axis being spaced away from the declination axis along the right ascension axis.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of Patent Cooperation Treaty(PCT) application No. PCT/CN2017/110668 having an international filingdate of 13 Nov. 2017. PCT application No. PCT/CN2017/110668 in turnclaims priority from Chinese application No. 201710637187.X filed 31Jul. 2017. All of the applications referenced in this paragraph arehereby incorporated herein by reference for all purposes.

TECHNICAL FIELD

The present invention relates to an equatorial mount for an opticalassembly. Some embodiments of the present invention relate to anequatorial mount for providing a telescope with a balanced weightdistribution.

BACKGROUND

Equatorial mounts have long been used for astronomical telescopes andcameras. Equatorial mounts compensate for Earth's rotation and providesingle-axis tracking of celestial objects.

The German equatorial mount, also referred to “GEM” for short, is knownin the art. A German equatorial mount typically has a right ascensionshaft, a declination shaft, and a counterweight shaft. The rightascension shaft is rotatable relative to the base about a rightascension axis. The declination shaft is rotatable relative to the rightascension shaft about a declination axis. The declination axis isorthogonal to the right ascension axis. The counterweight shaft ismounted to one end of the right ascension shaft and extends from theright ascension shaft along a counterweight axis that is co-linear withthe declination axis.

Typically, telescopes mounted on a German equatorial mount suffer froman unbalanced weight distribution. The unbalanced weight distributionmay decrease the structural stability of the mounted telescope and maycause the operation of the telescope to be relatively inconvenient.

There is a general desire for an equatorial mount for providing atelescope with a relatively more balanced weight distribution.

The foregoing examples of the related art and limitations relatedthereto are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification and a study of the drawings.

SUMMARY

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, tools and methods which aremeant to be exemplary and illustrative, not limiting in scope. Invarious embodiments, one or more of the above-described problems havebeen reduced or eliminated, while other embodiments are directed toother improvements.

One aspect of the invention provides an equatorial mount for an opticalassembly. The equatorial mount comprises a base; a declination basecoupled to the base and rotatable relative to the base about a rightascension axis, the declination base comprising a body and acounterweight assembly extending from the body along a counterweightaxis; and a device support supported by the declination base forrotation with the declination base about the right ascension axis, thedevice support rotatable relative to the declination base about adeclination axis. The right ascension axis is orthogonal to thedeclination axis. The declination axis intersects a midsection of thedeclination base. The counterweight axis is parallel to, and spacedapart from, the declination axis.

In some embodiments, the counterweight axis is spaced apart, in adirection parallel to the right ascension axis, from the declinationaxis.

In some embodiments, the body comprises first and second opposed endsand the midsection is located between, and spaced apart in a directionparallel to the right ascension axis from, each of the first and secondopposed ends.

The right ascension axis may be spaced away from the midsection in adirection parallel to the declination axis. Alternatively, the rightascension axis may intersect the midsection.

In some embodiments, the body has a declination base length measured inthe direction parallel to the right ascension axis between the first andsecond ends, and the midsection has a midsection length measured in thedirection parallel to the right ascension axis, the midsection lengthbetween 10%-80% of the declination base length. In other words, themidsection is spaced apart from each of the first and second ends by atleast 10% of the declination base length.

In some embodiments, the counterweight assembly extends from the firstend of the body along the counterweight axis.

In some embodiments, the counterweight assembly extends along thecounterweight axis from a location on the body that is more proximate tothe first end of the body than the declination axis.

The base may comprise a right ascension support extending axially alongthe right ascension axis. The right ascension support may comprise asleeve, the sleeve comprising a bore-defining surface that defines aright ascension bore that extends axially along the right ascensionaxis.

The body of the declination base may comprise first and second opposedends; and a first declination support at the first end, the firstdeclination support being rotatably coupled to the right ascensionsupport to thereby facilitate rotation of the declination base relativeto the base about the right ascension axis. The first declinationsupport may comprise a first declination-support sleeve shaped to definea first declination-support bore extending axially along the rightascension axis. The right ascension support may comprise a rightascension shaft portion which extends into the first declination-supportbore, the right ascension shaft portion comprising a bearing surfacethat bears against a bore-defining surface of the firstdeclination-support sleeve to provide the rotational coupling betweenthe first declination support and the right ascension support.

The body of the declination base may comprise a second declinationsupport at the second end to thereby facilitate rotation of thedeclination base relative to the base about the right ascension axis,the second declination support spaced apart from the first declinationsupport in a direction parallel with the right ascension axis.

The base may comprise a second right ascension support extending axiallyalong the right ascension axis and the second declination supportcomprises a second declination-support sleeve shaped to define a seconddeclination-support bore extending axially along the right ascensionaxis. The second right ascension support comprises a second rightascension shaft portion which extends into the seconddeclination-support bore, the second right ascension shaft portioncomprising a bearing surface that bears against a bore-defining surfaceof the second declination-support sleeve to provide the rotationalcoupling between the second declination support and the second rightascension support.

The right ascension support may bear against both the first and seconddeclination supports.

The equatorial mount may comprise a gear assembly operatively couplablebetween the declination base and the base, such that, when coupled,actuation of the gear assembly causes corresponding rotation of thedeclination base about the right ascension axis relative to the base.

Another aspect of the invention provides an equatorial mount mechanismwith stable load-bearing.

The equatorial mount mechanism with stable load-bearing, the equatorialmount may comprise a declination base, a right ascension shaft, an hourangle base bearing, a counterweight, an hour angle base, an hour anglelocking handle, a positioning key, a positioning recess, a counterweightlever, and a polar scope. The declination base may have a body that is acuboid. Two connecting frames (elsewhere may be referred to asdeclination supports) are designed at two ends below the body of thedeclination base. The hour angle base (elsewhere may be referred to as abase) has an upper portion and a lower portion coupled to each other byscrews. The upper portion and the lower portion may further be coupledby a positioning recess and a positioning key. The positioning key is anelongated protrusion located on the lower portion. A correspondingpositioning recess is located on the upper end. When the positioning keyis inserted into the corresponding positioning recess, the upper portion(comprising a right ascension support) is fixedly coupled to the lowerportion. A right ascension shaft may pass through the two connectingframes and the hour angle base. A polar scope may be coupled to theright ascension shaft at one end along the right ascension axis.Bearings can be used to assist with the rotation of declination baserelative to the base. The right ascension shaft may function as analignment and hinge pin to rotatably connect the declination base to thebase. An hour angle locking handle may be located on one end of theright ascension shaft. The lower portion of the base may be asemi-circular body; the right ascension shaft is connected in a fixedmanner to one end of the hour angle base, then a support bearing isinstalled on one end of the hour angle base and a support bearing isalso installed on a fixed hour angle shaft; then two ends of the hourangle base are connected to the two ends below the declination base. Thedeclination base and the hour angle base are both connected together bymeans of the right ascension shaft; the hour angle locking handle and adeclination locking handle are designed at two ends at the same side ofthe declination base respectively; the counterweight lever is designedbelow and to the right of the declination base; the counterweight leveris connected in a fixed manner to the declination base; thecounterweight is designed to be installed at a lower end of thecounterweight lever; and the counterweight is circularly annular andconnected in a fixed manner to the counterweight lever.

The right ascension shaft runs through an hour angle worm wheel; thehour angle worm wheel is connected in a fitted manner to the rightascension shaft; an hour angle worm is designed above the hour angleworm wheel; and the hour angle worm wheel is connected in a meshedmanner to the hour angle worm.

A support seat is disposed in the connecting frame below and to theright of the hour angle base; a fixing hole is designed on the hourangle base; a fixing bolt is designed on the support seat; the supportseat is connected in a fixed manner to the fixing hole on the hour anglebase by means of the fixing bolt; a latitude pedestal is designed belowthe support seat; a transverse latitude adjustment worm is designedabove the latitude pedestal; a screw-thread is designed on the latitudeadjustment worm; a fitted connection exists between the latitudeadjustment worm and the latitude pedestal; a latitude adjustment bevelgear is designed on the hour angle base; the latitude adjustment bevelgear is connected in a fitted manner to the hour angle base by means ofa rotary rod on the hour angle base; a gear groove is designed at anedge of a latitude adjustment worm wheel; and a meshed connection existsbetween the gear groove and the screw-thread on the latitude adjustmentworm.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thedrawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered illustrative rather than restrictive.

FIG. 1 is a perspective view of an equatorial mount according to a firstembodiment of the present invention.

FIG. 2 is a cross-sectional view of the equatorial mount of FIG. 1 takenthrough the centre of the equatorial mount along the line A-A.

FIG. 3 is an enlarged partial view of section B of the FIG. 1 equatorialmount.

FIG. 4 is a cross-sectional view of the equatorial mount of FIG. 1 takenalong the line C-C.

FIG. 5 is a perspective view of an equatorial mount according to asecond embodiment of the present invention.

FIG. 6 is a side elevation view of the equatorial mount of FIG. 5.

FIG. 7 is a cross-sectional view of the equatorial mount of FIG. 5 takenthrough the centre of the equatorial mount along the line D-D.

DETAILED DESCRIPTION

The present invention relates to an equatorial mount for a telescope orother optical instrument. Aspects of the invention relate to anequatorial mount for providing a telescope and/or the mount with arelatively more balanced weight distribution when compared to prior artequatorial mounts. The equatorial mount comprises a base, a declinationbase, and a device support. The declination base is coupled to the baseand is rotatable relative to the base about a right ascension axis. Thedeclination base comprises a body and a counterweight assembly extendingfrom the body along a counterweight axis. The device support issupported by the declination base for rotation with the declination baseabout the right ascension axis. The right ascension axis is orthogonalto the declination axis. The declination axis intersects a midsection ofthe declination base. The counterweight axis is parallel to, and spacedapart from, the declination axis. The counterweight axis may be spacedapart from the declination axis in a direction parallel with the rightascension axis. This arrangement lowers the center of gravity relativeto prior art equatorial mounts and leads to balanced weight distributionfor a telescope or other optical instrument mounted on the mount and/orfor the mount itself.

Two embodiments will be described in detail below to provide a morethorough understanding to persons skilled in the art. However, a personskilled in the art would understand that additional and/or alternativeembodiments consistent with this disclosure are also possible.

In both embodiments, the base comprises a right ascension supportextending axially along the right ascension axis. The declination basecomprises a first declination support that is rotatably coupled to theright ascension support to thereby facilitate rotation of thedeclination base relative to the base about the right ascension axis.

The two embodiments differ from each other. In the first embodiment, theright ascension support comprises a sleeve, the sleeve comprising abore-defining surface that defines a right ascension bore that extendsaxially along the right ascension axis. A first declination support ofthe first embodiment comprises a declination shaft portion which extendsinto the right ascension bore, the declination shaft portion comprisinga bearing surface that bears against a bore-defining surface of theright ascension sleeve to provide the rotational coupling between thefirst declination support and the right ascension support.

In the second embodiment, the first declination support comprises afirst declination-support sleeve shaped to define a firstdeclination-support bore extending axially along the right ascensionaxis. The right ascension support comprises a right ascension shaftportion which extends into the first declination-support bore, the rightascension shaft portion comprising a bearing surface that bears againsta bore-defining surface of the first declination-support sleeve toprovide the rotational coupling between the first declination supportand the right ascension support.

Throughout the following description specific details are set forth inorder to provide a more thorough understanding to persons skilled in theart. However, well known elements may not have been shown or describedin detail to avoid unnecessarily obscuring the disclosure. Accordingly,the description and drawings are to be regarded in an illustrative,rather than a restrictive, sense.

First Embodiment

FIGS. 1 to 4 show an example embodiment of an equatorial mount 100. FIG.1 is a perspective view of equatorial mount 100 showing the lines alongwhich the two selected cross-sections are taken. FIG. 2 is across-sectional view of equatorial mount 100 taken through the centre ofequatorial mount 100 along the line A-A, schematically illustratingelements of equatorial mount 100. FIG. 3 is a partially enlarged view ofa counterweight assembly 108. FIG. 4 is a cross-section view ofequatorial mount 100 taken along the line C-C.

Equatorial mount 100 comprises a base 102, a declination base 104, and adevice support 106. These components are linked in the followingarrangement:

-   -   Base 102 is stationary relative to a right ascension axis 110.        Base 102 typically includes components (not expressly        enumerated) for coupling mount 100 to a tripod.    -   Declination base 104 is rotatably coupled to base 102.        Declination base 104 is rotatable about right ascension axis 110        relative to base 102.    -   Device support 106 is coupled to declination base 104. Device        support 106 is rotatable about a declination axis 112 relative        to declination base 104. Device support 106 is also rotatable        about right ascension axis 110 in a sense because device support        106 moves with declination base 104 when declination base 104        rotates about right ascension axis 110 relative to base 102.

Base 102 does not rotate about right ascension axis 110. Base 102comprises a right ascension support 126. In the illustrated embodimentof FIGS. 1-4, right ascension support 126 comprises a sleeve that is inthe shape of a hollow (generally annular) tube that has a bore-definingsurface 194 that defines a right ascension bore 196 that extends axiallyalong right ascension axis 110—i.e. right ascension axis 110 extendsalong an axial center of bore 196 defined by bore-defining surface 194of right ascension support 126.

Right ascension support 126 comprises first and second opposed open ends134, 136 and right ascension support 126 extends from first open end 134to second open end 136 along right ascension axis 110. Right ascensionsupport 126 can be of any suitable configuration and/or shape as long asright ascension support 126 functions to support declination base 104along right ascension axis 110 and permit rotation of declination base104 relative to right ascension axis 110. For example, in someembodiments, right ascension support 126 may be a solid tube axiallyaligned along right ascension axis 110. Another embodiment of rightascension support 126 is shown in FIGS. 5 to 7.

Base 102 comprises a lower portion 142 extends downwardly from rightascension support 126. Lower portion 142 and right ascension support 126may be integrally formed as one piece. Alternatively, lower portion 142and right ascension support 126 may be individually formed and may thenbe coupled together in any suitable manner known in the art. Forexample, right ascension support 126 and lower portion 142 may connectedby screws. To reinforce the connection between right ascension support126 and lower portion 142, a locking mechanism may be used. The lockingmechanism of the illustrated embodiment of FIGS. 1-4 comprises apositioning protrusion 178 on lower portion 142 and a correspondingpositioning recess 180 on right ascension support 126. When positioningprotrusion 178 is inserted into positioning recess 180, the fixedconnection between right ascension support 126 and lower portion 142 isreinforced.

Through lower portion 142, right ascension support 126 may sit on and becoupled to a latitude adjustment assembly 114. Latitude adjustmentassembly 114 is for aligning mount 100 so that the angle of altitudeadjustment assembly 114 is set to be approximately the same as thelatitude where mount 100 is used. In the illustrated embodiment and asbetter shown in FIG. 1, lower portion 142 has a through-hole. A bolt isextended through the through hole to form an attachment 116 and tothereby connect lower portion 142 to latitude adjustment assembly 114.Right ascension support 126 may be rotatable about the centreline ofattachment 116 to allow polar alignment. A person skilled the in artwould understand that lower portion 142 can be coupled to latitudeadjustment assembly 114 by any suitable means.

Declination base 104 comprises a body 146 and a counterweight assembly108 extending from body 146 along a counterweight axis 186 (FIG. 2).Counterweight axis 186 is parallel to, and spaced apart from,declination axis 112. Counterweight axis 186 may be spaced apart fromdeclination axis 112 in a direction that is parallel with rightascension axis 110.

Body 146 comprises first and second opposed ends 118, 120 spaced apartalong a direction 184 that is parallel to right ascension axis 110. Amidsection 124 is located between, and spaced apart in a directionparallel to right ascension axis 110 from, the first and second opposedends 118, 120. Body 146 has a declination base length measured indirection 184 between first and second ends 118, 120. Midsection 124 hasa midsection length measured in direction 184 and the midsection lengthmay be between 10%-80% of the declination base length, including anyvalue therebetween, e.g. 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, and 75%. In other words, body 102 has a declination baselength measured in direction 184 between first and second ends 118, 120.Midsection 124 may be spaced apart from each of first and second ends118, 120 by at least 10% of the declination base length.

Body 146 of the illustrated embodiment of FIGS. 1-4 comprises a pair ofdeclination supports 148, 150 extending from first and second opposedends 118, 120, respectively. First and second supports 148, 150 arerotatably coupled to right ascension support 126 to thereby facilitaterotation of declination base 104 relative to base 102 about rightascension axis 110. First and second declination supports 148, 150 maybe axially aligned along right ascension axis 110.

First declination support 148 comprises a declination shaft portion 130that extends into right ascension bore 196 of right ascension support126. Declination shaft portion 130 comprises a bearing surface 198 thatbears against the bore-defining surface 194 of right ascension support126 to provide the rotational coupling between declination support 148and right ascension support 126.

Second declination support 150 comprises a second declination-supportsleeve shaped to define a second declination-support bore extendingaxially along the right ascension axis 110—i.e. a centerline of thesecond declination-support bore may extend along the right ascensionaxis 110.

In other embodiments, first and second declination supports 148, 150 canbe of any suitable configurations and shapes as long as first and seconddeclination supports 148, 150 can be coupled to base 102 (e.g. to rightascension support 126) to enable rotation of declination base 104relative to base 102 about right ascension axis 110.

Counterweight assembly 108 may be configured to achieve balance aboutright ascension axis 110 and/or to otherwise help to balance mount 100.Counterweight assembly 108 comprises a counterweight shaft 164 and acounterweight mass 166. Counterweight shaft 164 is attached to andextends from first declination support 148 along counterweight axis 186.Counterweight axis 186 is spaced away from declination axis 112.Counterweight axis 186 may be space apart from declination axis 112 in adirection parallel with right ascension axis 110.

Declination base 104 is coupled to base 102 and is rotatable relative tobase 102 about right ascension axis 110. In the illustrated embodiment,declination supports 148, 150 and right ascension support 126 providethe rotatable connection between declination base 104 and base 102.

To connect right ascension support 126 with first declination support148, declination shaft portion 130 of first declination support 148 isinserted into right ascension support 126 so that the bearing surface ofdeclination shaft portion 130 bears against the bore-defining surface ofright ascension support 126.

To connect right ascension support 126 with second declination support150, a polar scope 132 in inserted into the bore of right ascensionsupport 126 and the bore of second declination support 150. Polar scope132 functions as an alignment and hinge pin along right ascension axis110.

Other structural arrangements are possible to rotatably coupledeclination base 104 with base 102, so that declination base 104 isrotatable relative to base 102 about right ascension axis 110. Forexample, in some embodiments, body 146 comprises only one declinationsupport in the shape of a generally hollowed-out (e.g. annular ortubular) cylinder (instead of two declination supports as shown in theillustrated embodiment). Such a declination support may extend fromfirst end 118 to second end 120 of body 146 of declination base 104.Such a declination support may axially and concentrically surround rightascension support 126 and be rotatable relative to right ascensionsupport 126 about right ascension axis 110. In another embodiment,declination supports 148, 150 and right ascension support 126 may eachprovide a bore extending axially along right ascension axis 110. Rightascension support 126 may be located (in a direction parallel with rightascension axis 110) between declination supports 148, 150. An alignmentand hinge pin may be inserted within the axially aligned bores of suchdeclination supports 148, 150 and right ascension support 126.

Bearings 160 between declination base 104 and base 102 may be present tofurther assist in permitting relative rotation of declination base 104relative to base 102 about right ascension axis 110.

To actuate rotation of declination base 104 relative to base 102 aboutright ascension axis 110, right ascension gear assembly 128 may be used.Gear assembly 128 may be coupled to declination base 104. Actuation ofgear assembly 128 may cause corresponding rotation of declination base104 about right ascension axis 110 relative to base 102. In theparticular case of the illustrated embodiment of FIGS. 1-4, gearassembly 128 comprises a worm gear 140 and a worm wheel 138, such thatactuation of worm gear 140 causes corresponding rotation of declinationbase 104 about right ascension axis 110 relative to base 102.

Gear assembly 128 may be driven by a motor 190 allowing motorizedrotation of declination base 104 about right ascension axis 110. Aperson skilled in the art would understand that motor 190 may be coupledto declination base 104 to drive declination base 104 about rightascension axis 110 without the use of gearing. Motor 190 is housedwithin body 146.

In some embodiments, gear assembly 128 comprises a worm wheel 138 and aworm gear 140. Worm wheel 138 may be coupled to right ascension shaft130 and worm gear 140 may be coupled to declination base 104. Rotationof worm gear 140 may cause worm wheel 138 and thus declination base 104to rotate about right ascension axis 110.

Device support 106 comprises a declination shaft 144. Declination shaft144 extends axially along declination axis 112 relative to declinationbase 104 i.e. an axial centerline of declination shaft 144 may beco-linear with declination axis 112. Declination shaft 144 is rotatableabout declination axis 112 relative to declination base 104 and isrotatable with declination base 144 about right ascension axis 110.

To enable rotation of declination shaft 144 relative to declination base104 about declination axis 112, declination gear assembly 152 may beused. Declination gear assembly 152 may be coupled to declination base104. Actuation of declination gear assembly 152 may cause correspondingrotation of declination shaft 144 about declination axis 112 relative todeclination base 104. Declination gear assembly 152 may comprise a wormgear 156 and a worm wheel 154, such that actuation of worm gear 156causes corresponding rotation of declination shaft 144 about declinationaxis 112 relative to declination base 104.

In the illustrated embodiment of FIGS. 1-4, declination gear assembly152 is driven by a motor 192, allowing motorized rotation of declinationshaft 144 about declination axis 112. A person skilled in the art wouldunderstand that motor 192 may be coupled to declination shaft 144 todrive declination shaft 144 about declination axis 112 without the useof gearing. Motor 192 may be housed within body 146.

When a telescope or other optical device (not shown) is mounted onequatorial mount 100, rotation of declination shaft 144 aboutdeclination axis 112 rotates the optical device about declination axis112. Rotation of declination base 104 about right ascension axis 110causes the optical device to rotate about right ascension axis 110.Declination axis 112 intersects orthogonally with right ascension axis110 and declination axis 112 intersects midsection 124 of declinationbase 104. Counterweight axis 186 is spaced away from declination axis112. Counterweight axis 186 may be spaced apart from declination axis122 in a direction parallel to right ascension axis 110. An advantage ofthis arrangement is to lower the center of gravity of an optical devicemounted on equatorial mount 100 and/or the center of gravity of mount100 itself.

As shown in FIG. 2, right ascension axis 110 may be spaced away frommidsection 124 in a direction parallel to declination axis 112. In someembodiments, right ascension axis 110 intersects midsection 124.

The body of the declination base may be a cuboid; two connecting frames(elsewhere referred to as declination supports) are designed at two endsbelow the body of the declination base; the hour angle base is dividedinto an upper portion and a lower portion; the upper and lower portionsof the hour angle base are connected by a screw; the positioning key isdesigned at a position in the middle of the upper and lower portions ofthe hour angle base; the positioning key takes the form of a long,protruding strip; two positioning recesses are designed at a middleposition of the right ascension shaft, opposite a position of thepositioning key; the positioning recess takes the form of a long,recessed strip; the positioning key and the positioning recess fit eachother; the positioning key is inserted into the positioning recess; theright ascension shaft is connected in a fixed manner to the hour anglebase; the right ascension shaft runs through the connecting frames atthe two ends below the declination base and through the hour angle base;a polar scope is designed at a left end of the right ascension shaft;one end of a polar scope shaft is inserted into the right ascensionshaft, another end being connected to the connecting frame at a left endof the declination base; the hour angle base bearing is disposed atpositions of convergence of two ends of the right ascension shaft andthe connecting frames of the declination base; the declination base andthe hour angle base are both connected together by means of the rightascension shaft; the hour angle locking handle is designed at an outerside of the hour angle base bearing at a right end of the rightascension shaft; the hour angle locking handle is connected in a fixedmanner to the right ascension shaft; the counterweight lever is designedbelow and to the right of the declination base; the counterweight leveris connected in a fixed manner to the declination base; thecounterweight is designed to be installed at a lower end of thecounterweight lever; and the counterweight is circularly annular andconnected in a fixed manner to the counterweight lever.

The right ascension shaft runs through an hour angle worm wheel; thehour angle worm wheel is connected in a fitted manner to the rightascension shaft; an hour angle worm is designed above the hour angleworm wheel; and the hour angle worm wheel is connected in a meshedmanner to the hour angle worm.

A support seat is disposed in the connecting frame below and to theright of the hour angle base; a fixing hole is designed on the hourangle base; a fixing bolt is designed on the support seat; the supportseat is connected in a fixed manner to the fixing hole on the hour anglebase by means of the fixing bolt; a latitude pedestal is designed belowthe support seat; a transverse latitude adjustment worm is designedabove the latitude pedestal; a screw-thread is designed on the latitudeadjustment worm; a fitted connection exists between the latitudeadjustment worm and the latitude pedestal; a latitude adjustment wormwheel is designed on the hour angle base; the latitude adjustment wormwheel is connected in a fitted manner to the hour angle base by means ofa rotary rod on the hour angle base; a gear groove is designed at anedge of the latitude adjustment worm wheel; and a meshed connectionexists between the gear groove and the screw-thread on the latitudeadjustment worm.

During use of the present utility model, by designing such aload-bearing mechanism, when the declination base rotates relative tothe right ascension shaft, due to the fact that the counterweight isconnected in a fixed manner to the declination base, the counterweightalso rotates as the declination base rotates, the center of gravity ofthe equatorial mount is lowered, and load-bearing is heavier, increasingthe stability of the equatorial mount.

Second Embodiment

FIGS. 5 to 7 show a second example embodiment of an equatorial mount200. Equatorial mount 200 is generally similar to equatorial mount 100as shown in FIGS. 1-4 and like elements have been illustrated withreference numerals incremented by 100 and are not further describedagain.

Equatorial mount 200 comprises a base 202; a declination base 204, and adevice support 206. Declination base 204 is rotatably coupled to base202. Declination base 204 is rotatable about right ascension axis 210relative to base 202. Device support 206 is coupled to declination base204. Device support 206 is rotatable about a declination axis 212relative to declination base 204. Device support is also rotatable aboutright ascension axis 210 in a sense because device support 206 moveswith declination base 204 when declination base 204 rotates about rightascension axis 210 relative to base 202.

Declination base 204 comprises a body 246 and a counterweight assembly208 extending from body 246 along a counterweight axis 286.Counterweight axis 286 is parallel to, and spaced apart from,declination axis 212.

Body 246 comprises first and second opposed ends 218, 2220 spaced apartalong a direction 284 that is parallel to right ascension axis 210. Amidsection 224 is located between, and spaced apart in a directionparallel to right ascension axis 210 from, the first and second opposedends 218, 220. Body 246 has a declination base length measured indirection 284 between first and second ends 218, 220. Midsection 224 hasa midsection length measured in direction 284 and the midsection lengthis between 10%-80% of the declination base length, including any valuetherebetween, e.g. 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, and 75%. In other words, body 202 has a declination baselength measured in direction 284 between first and second ends 218, 220.Midsection 224 is spaced apart from each of first and second ends 218,220 by at least 10% of the declination base length.

Body 246 comprises a pair of declination supports 248, 250. Firstdeclination support 248 extends from first end 218 of body 246 along adirection that is parallel to declination axis 212. Second declinationsupport extends from second end 220 of body 246 along a direction thatis parallel to declination axis 212. First and second declinationsupports 248, 250 each are axially aligned along right ascension axis210. In the illustrated embodiment of FIGS. 5-7, declination supports248, 250 each is a sleeve in the shape of a generally hollowed-outcylinder. First and second declination supports 248, 250 each define adeclination-support bore extending axially along right ascension axis210. In other embodiments, declination supports 248, 250 can be of anysuitable configurations and shapes as long as declination supports 248,250 can be coupled to base 202 to enable rotation of declination base204 relative to base 202 about right ascension axis 210.

Base 202 comprises first and second right ascension support 226, 226′and a lower portion 242.

First and second right ascension supports 226, 226′ are spaced apartfrom each other long right ascension axis 2210. First and second rightascension supports 226, 226′ each comprise a right ascension shaftportion. The first right ascension shaft portion is configured to extendinto the first declination-support bore. The second right ascensionshaft portion is configured to extend into the seconddeclination-support bore. Each one of the right ascension shaft portionscomprises a bearing surface to bear against a bore-defining surface ofthe corresponding declination-support bore to provide the rotationalcoupling between the first declination support and the right ascensionsupport.

Lower portion 242 connects first and second right ascension support 226,226′. Lower portion 242 extends downwardly from first and second rightascension support 226, 226′. Lower portion 242 is similar to a crescentmoon shape having a curved body 274 and first and second ends 276, 278.First and second ends 276, 278 are coupled to first and second rightascension support 226, 226′, respectively.

Curved body 274 may be coupled to a latitude adjustment assembly 214 foraligning mount 200 so that the angle of altitude adjustment assembly 214is set to be approximately the same as the latitude where mount 200 isused.

Declination base 204 is coupled to base 202 and is rotatable relative tobase 202 about right ascension axis 210. In the illustrated embodimentof FIGS. 5-7, the rotatable connection between declination base 204 andbase 202 is provided by (i) the hinge connection between firstdeclination support 248 and first right ascension support 226 and (ii)the hinge connection between second declination support 250 and secondright ascension support 226′.

To connect first right ascension support 226 with first declinationsupport 248, the right ascension shaft 230 is inserted into the bore offirst declination support 248 so that the bearing surface of first rightascension support 226 bears against the bore defining surface of firstdeclination support sleeve 248. To connect second right ascensionsupport 226′ with second declination support 226, the right ascensionshaft 230 is inserted into the bore of first declination support 248 sothat the bearing surface of second right ascension support 226 bearsagainst the bore defining surface of second declination support sleeve248.

First right ascension support 226 is positioned between first and seconddeclination supports 248, 250 axially along right ascension axis 210. Incontrast to equatorial mount 100, first right ascension support 226 isnot connected to second declination support 250 and thereby a space isprovided between first right ascension support 226 and seconddeclination support 250 along right ascension axis 210. In analternative embodiment, first ascension support 226 bears against bothfirst and second declination supports 248, 250.

Also in contrast to equatorial mount 100, polar scope 232 is attached todeclination body 246 and is disposed axially in a direction that isparallel to and away from right ascension axis 210.

1. An equatorial mount for an optical assembly, the equatorial mountcomprising: a base; a declination base coupled to the base and rotatablerelative to the base about a right ascension axis, the declination basecomprising a body and a counterweight assembly extending from the bodyalong a counterweight axis; and a device support supported by thedeclination base for rotation with the declination base about the rightascension axis, the device support rotatable relative to the declinationbase about a declination axis; wherein: the right ascension axis isorthogonal to the declination axis; the declination axis intersects amidsection of the declination base; and the counterweight axis isparallel to, and spaced apart from, the declination axis.
 2. Anequatorial mount as defined in claim 1, wherein the counterweight axisis spaced apart, in a direction parallel to the right ascension axis,from the declination axis.
 3. An equatorial mount as defined in claim 1,wherein the body comprises first and second opposed ends and themidsection is located between, and spaced apart in a direction parallelto the right ascension axis from, each of the first and second opposedends.
 4. An equatorial mount as defined in claim 1, wherein the rightascension axis is spaced away from the midsection in a directionparallel to the declination axis.
 5. An equatorial mount as defined inclaim 1, wherein the right ascension axis intersects the midsection. 6.An equatorial mount as defined in claim 3, wherein the body has adeclination base length measured in the direction parallel to the rightascension axis between the first and second ends, and wherein themidsection has a midsection length measured in the direction parallel tothe right ascension axis, the midsection length between 10%-80% of thedeclination base length.
 7. An equatorial mount as defined in claim 3,the body having a declination base length measured in the directionparallel to the right ascension axis between the first and second ends,and wherein the midsection is spaced apart from each of the first andsecond ends by at least 10% of the declination base length.
 8. Anequatorial mount as defined in claim 3, wherein the counterweightassembly extends from the first end of the body along the counterweightaxis.
 9. An equatorial mount as defined in claim 3, wherein thecounterweight assembly extends along the counterweight axis from alocation on the body that is more proximate to the first end of the bodythan the declination axis.
 10. An equatorial mount as defined in claim1, wherein the base comprises a right ascension support extendingaxially along the right ascension axis.
 11. An equatorial mount asdefined in claim 10, wherein the right ascension support comprises asleeve, the sleeve comprising a bore-defining surface that defines aright ascension bore that extends axially along the right ascensionaxis.
 12. An equatorial mount as defined in claim 10, wherein the bodyof the declination base comprises: first and second opposed ends; and afirst declination support at the first end, the first declinationsupport being rotatably coupled to the right ascension support tothereby facilitate rotation of the declination base relative to the baseabout the right ascension axis.
 13. An equatorial mount as defined inclaim 12, wherein: the first declination support comprises a firstdeclination-support sleeve shaped to define a first declination-supportbore extending axially along the right ascension axis; and the rightascension support comprises a right ascension shaft portion whichextends into the first declination-support bore, the right ascensionshaft portion comprising a bearing surface that bears against abore-defining surface of the first declination-support sleeve to providethe rotational coupling between the first declination support and theright ascension support.
 14. An equatorial mount as defined in claim 12,wherein the body of the declination base comprises a second declinationsupport at the second end to thereby facilitate rotation of thedeclination base relative to the base about the right ascension axis,the second declination support spaced apart from the first declinationsupport in a direction parallel with the right ascension axis.
 15. Anequatorial mount as defined in claim 14, wherein: the base comprises asecond right ascension support extending axially along the rightascension axis; the second declination support comprises a seconddeclination-support sleeve shaped to define a second declination-supportbore extending axially along the right ascension axis; and the secondright ascension support comprises a second right ascension shaft portionwhich extends into the second declination-support bore, the second rightascension shaft portion comprising a bearing surface that bears againsta bore-defining surface of the second declination-support sleeve toprovide the rotational coupling between the second declination supportand the second right ascension support.
 16. An equatorial mount asdefined in claim 14, wherein the right ascension support bears againstboth the first and second declination supports.
 17. An equatorial mountas defined in claim 1, wherein the equatorial mount comprises a gearassembly operatively couplable between the declination base and thebase, such that, when coupled, actuation of the gear assembly causescorresponding rotation of the declination base about the right ascensionaxis relative to the base.
 18. An equatorial mount mechanism with stableload-bearing, characterized in that it comprises a declination base, aright ascension shaft, an hour angle base bearing, a counterweight, anhour angle base, an hour angle locking handle, a positioning key, apositioning recess and a counterweight lever; the declination base is acuboid; two connecting frames are designed at two ends below thedeclination base; the hour angle base is a semi-circular body; the rightascension shaft is connected in a fixed manner to one end of the hourangle base, then a support bearing is installed on one end of the hourangle base and a support bearing is also installed on a fixed hour angleshaft; then two ends of the hour angle base are connected to the twoends below the declination base. The declination base and the hour anglebase are both connected together by means of the right ascension shaft;the hour angle locking handle and a declination locking handle aredesigned at two ends at the same side of the declination baserespectively; the counterweight lever is designed below and to the rightof the declination base; the counterweight lever is connected in a fixedmanner to the declination base; the counterweight is designed to beinstalled at a lower end of the counterweight lever; and thecounterweight is circularly annular and connected in a fixed manner tothe counterweight lever.
 19. The equatorial mount mechanism with stableload-bearing as claimed in claim 18, characterized in that the rightascension shaft runs through an hour angle worm wheel; the hour angleworm wheel is connected in a fitted manner to the right ascension shaft;an hour angle worm is designed above the hour angle worm wheel; and thehour angle worm wheel is connected in a meshed manner to the hour angleworm.
 20. The equatorial mount mechanism with stable load-bearing asclaimed in claim 18, characterized in that a support seat is disposed inthe connecting frame below and to the right of the hour angle base; afixing hole is designed on the hour angle base; a fixing bolt isdesigned on the support seat; the support seat is connected in a fixedmanner to the fixing hole on the hour angle base by means of the fixingbolt; a latitude pedestal is designed below the support seat; atransverse latitude adjustment worm is designed above the latitudepedestal; a screw-thread is designed on the latitude adjustment worm; afitted connection exists between the latitude adjustment worm and thelatitude pedestal; a latitude adjustment bevel gear is designed on thehour angle base; the latitude adjustment bevel gear is connected in afitted manner to the hour angle base by means of a rotary rod on thehour angle base; a gear groove is designed at an edge of the latitudeadjustment bevel gear; and a meshed connection exists between the geargroove and the screw-thread on the latitude adjustment worm.